1. Field of the Invention
The present invention is related to semiconductor processing, and in particular to semiconductor devices and the manufacturing thereof using plasma assisted oxide processes and chemical mechanical polishing.
2. Description of the Related Art
The fabrication of semiconductor trenches can result in sharp trench corners at the top of the trench walls. These sharp trench corners can interfere with the deposition of layers of uniform thickness thereon, and so can hinder the formation of layers adjacent to the trench.
Some conventional processes first form a trench, then utilize a high-density plasma (HDP) vapor deposition process to fill the trench to provide shallow trench isolation (STI). A chemical mechanical polishing (CMP) planarization process is then conventionally used to reduce the sharp trench corners, as well as to reduce dishing and nitride erosion. However, much of the slurry used during the CMP process is sometimes wasted or inefficiently used. This is particularly true, by way of example, of Cerium Oxide (CeO2) slurry, which is sensitive to topology, such as sharp corners. Thus, in some instances, it would be advantageous to enhance the polishing efficiency and to reduce slurry waste by reducing the sharp trench corners before performing CMP planarization.